Donepezil has been shown to have good success in improving cognitive impairment in patients with Alzheimer's disease. Pilot studies conducted at University Hospital at Stony Brook have demonstrated that donepezil could be a well-tolerated and effective intervention for the memory impairment experienced by individuals with MS. The present study seeks to explore the efficacy of donepezil in improving the cognitive impairments found in MS. Specifically, we plan to compare the performance of 20 MS patients administered donepezil, with 20 MS patients receiving placebo treatment, on a battery of neuropsychological test. It is hypothesized a greater proportion of MS patients treated with donepezil will show improvement in verbal memory that those treated with placebo.